Computer Networking & Hardware Concepts.pdf

Tools for
Teaching Computer
Networking and
Hardware Concepts
NurulI.Sarkar,AucklandUniversityofTechnology,NewZealand
Hershey • London • Melbourne • Singapore
Information Science Publishing

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Library of Congress Cataloging-in-Publication Data
Tools for teaching computer networking and hardware concepts / Nurul Sarkar, editor.
p. cm.
Summary: "This book offers concepts of the teaching and learning of computer networking
and hardwar eby offering undamental theoretical concepts illustrated with the use of
interactive practical exercises"--Provided by publisher.
Includes bibliographical references and index.
ISBN 1-59140-735-4 (h/c) -- ISBN 1-59140-736-2 (s/c) -- ISBN 1-59140-737-0 (ebook)
1. Computer networks--Study and teaching. 2. Computer input-output equipment--Study
and teaching. I. Sarkar, Nurul.
TK5105.5.T66 2006
004.6071--dc22
2005027411
British Cataloguing in Publication Data
A Cataloguing in Publication record for this book is available from the British Library.
All work contributed to this book is new, previously-unpublished material. The views
expressed in this book are those of the authors, but not necessarily of the publisher.

Dedication
To my wife, Laila A. Sarkar

Tools for Teaching
Computer Networking
and Hardware Concepts
Table of Contents
Foreword ........................................................................................................ viii
Preface .............................................................................................................. ix
Section I: Introduction
Chapter I. Introduction to Computer Networking and Hardware
Concepts ........................................................................................................... 1
Nurul I. Sarkar, Auckland University of Technology, New Zealand
Section II: Teaching and Learning Computer Networking
Chapter II. WebLan-Designer: A Web-Based Tool to Enhance
Teaching and Learning Wired and Wireless LAN Design ..................... 21
Krassie Petrova, Auckland University of Technology, New Zealand
Chapter III. INetwork: An Interactive Learning Tool for
Communication Networks ............................................................................ 39
K. Sandrasegaran, The University of Technology Sydney,
Australia
M. Trieu, The University of Technology Sydney, Australia

Chapter IV. Effectively Using a Network Simulation Tool to Enhance
Students’ Understanding of Computer Networking Concepts .............. 62
Cecil Goldstein, Queensland University of Technology, Australia
Karen Stark, Queensland University of Technology, Australia
Susanna Leisten, Queensland University of Technology, Australia
Alan Tickle, Queensland University of Technology, Australia
Chapter V. Teaching Protocols through Animation ................................. 86
Kenneth J. Turner, University of Stirling, UK
Chapter VI. Enhancing Student Understanding of Packet-Forwarding
Theories and Concepts with Low-Cost Laboratory Activities............. 101
Anthony P. Kadi, The University of Technology Sydney, Australia
Chapter VII. Ethereal: A Tool for Making the Abstract Protocol a
Concrete Reality .......................................................................................... 119
David Bremer, Otago Polytechnic, New Zealand
Section III: Wireless Networking and Information Security
Chapter VIII. Enhancing Teaching and Learning Wireless
Communication Networks Using Wireless Projects.............................. 135
Trevor Craig, Wollongong College Auckland, New Zealand
Chapter IX. Teaching and Learning Wi-Fi Networking
Fundamentals Using Limited Resources................................................. 154
Wilson Siringoringo, Auckland University of Technology,
New Zealand
Nurul I. Sarkar, Auckland University of Technology,
New Zealand
Chapter X. Information Security Risk Analysis: A Pedagogic
Model Based on a Teaching Hospital ...................................................... 179
Sanjay Goel, University at Albany, SUNY, and NYS Center for
Information Forensics and Assurance, USA
Damira Pon, University at Albany, SUNY, and NYS Center for
Information Forensics and Assurance, USA

Section IV: Teaching and Learning Computer Hardware
Chapter XI. A Practical Introduction to Input and Output Ports......... 201
David L. Tarnoff, East Tennessee State University, USA
Chapter XII. Enhancing Teaching and Learning Computer
Hardware Fundamentals Using PIC-Based Projects ............................. 229
New Zealand
Trevor Craig, Wollongong College Auckland, New Zealand
Chapter XIII. Assistant Tool for Instructors Teaching Computer
Hardware with the PBL Theory ................................................................ 249
Maiga Chang, National Science and Technology Program for
e-Learning, Taiwan
Kun-Fa Cheng, Chih-Ping Senior High School, Taiwan
Alex Chang, Yuan-Ze University, Taiwan
Ming-Wei Chen, Chih-Ping Senior High School, Taiwan
Chapter XIV. A Simulator for High-Performance Processors ............. 267
John Morris, University of Auckland, New Zealand
Chapter XV. A Remotely Accessible Embedded Systems
Laboratory .................................................................................................... 284
Steve Murray, The University of Technology Sydney, Australia
Vladimir Lasky, The University of Technology Sydney, Australia
Chapter XVI. LOGIC-Minimiser: A Software Tool to Enhance
Teaching and Learning Minimization of Boolean Expressions............ 303
New Zealand
Khaleel I. Petrus, University of Southern Queensland, Australia
Section V: Data Communication Protocols and Learning Tools
Chapter XVII. A Practical Introduction to Serial Protocols ................. 319
David L. Tarnoff, East Tennessee State University, USA

Chapter XVIII. VMware as a Practical Learning Tool .......................... 338
Eduardo Correia, Christchurch Polytechnic Institute of
Technology, New Zealand
Ricky Watson, Christchurch Polytechnic Institute of Technology,
New Zealand
Appendix Section ......................................................................................... 355
Glossary......................................................................................................... 359
About the Authors ....................................................................................... 375
Index .............................................................................................................. 383

Foreword
viii
Computer networking and hardware concepts have come alive! With Tools for
Teaching Computer Networking and Hardware Concepts, the teaching and
learning of computer networking and hardware are made more interesting and
applied. Fundamental theoretical concepts are illustrated with the use of inter-
active practical exercises.
Each chapter presents learning objectives, figures and illustrations, real-world
examples as well as review questions, all of which provides teachers and stu-
dents with a resource to enhance learning.
This book is somewhat unique in that it brings together experiences from aca-
demics in countries such as Scotland, Taiwan, the United States of America,
Australia, and New Zealand. In sharing their use of online tools and flexible
learning practices, I hope that you will find this book a useful resource in the
teaching and learning of computer networking and hardware essentials.
Dr. Felix B. Tan
Professor of Information Systems and Head
School of Computer and Information Sciences
Auckland University of Technology
New Zealand

ix
Preface
Because of the high demand for networking and hardware skills in commerce
and in industry worldwide, computer networking and hardware courses are
becoming increasingly popular in universities, polytechnic institutions,
postsecondary colleges, and private training institutions around the globe. De-
spite this, it is often difficult to motivate students to learn computer networking
and hardware concepts because students appear to find the subject technical
and rather dry and boring. We strongly believe, as do many others, that students
learn computer networking and hardware fundamentals better and feel more
engaged with their courses if they are given interactive practical exercises that
illustrate theoretical concepts.
There are numerous textbooks on computer networking and hardware con-
cepts as well as publications, including journals and conference proceedings, in
computer education and Web-based learning. However, these publications have
very limited discussion on software and hardware tools that enhance teaching
and learning computer networking and hardware concepts. To address this need,
we have written Tools for Teaching Computer Networking and Hardware
Concepts, focusing on the development and use of innovative tools for teaching
and learning various aspects of computer networking and hardware concepts.
We believe the proposed book is unique and is a useful resource to both stu-
dents and teachers at university, polytechnic, postsecondary, and private train-
ing institutions. This book: (1) provides comprehensive coverage of tools and
techniques for teaching and learning computer networking and hardware con-
cepts at introductory and advanced levels; (2) can be used as a resource both
by students and by teachers in different teaching and learning contexts; (3)
offers both students and teachers an opportunity to benefit from the experience
of teachers and researchers in other countries in the areas of teaching and

x
learning computer networking and hardware; (4) represents a rich starting point
for researchers interested in developing innovative tools for teaching and learn-
ing computer networking and hardware concepts; and (5) raises the awareness
of the need to enhance face-to-face teaching through the use of online interac-
tive learning and flexible mode of delivery of papers. Although various hard-
ware and software tools, methods, and laboratory settings are discussed in the
text, an emphasis has been placed on the development and use of tools and
techniques in the classroom that enhance the teaching and learning of various
aspects of computer networking and hardware concepts.
Organization and Outline
The book is organized into five sections.
Section I: Introduction. Section I (Chapter I) provides a rationale and intro-
duction to the book. It provides an introduction to computer networking and
hardware concepts and highlights the use of software and hardware tools as an
aid to enhance teaching and learning computer networking and hardware fun-
damentals. It also outlines the remainder of this book.
Section II: Teaching and Learning Computer Networking. Section II con-
sists of six chapters (II through VII) and provides detailed coverage of the
software and hardware tools and lab activities designed to enhance teaching
and learning various aspects of computer networking. Chapter II describes the
development and use of an interactive software tool (named WebLan-Designer)
as an aid to enhance teaching and learning both wired and wireless LAN de-
sign. Chapter III describes INetwork, an interactive learning tool for communi-
cation networks. Chapter IV emphasizes the use of a network simulation tool in
large classes to enhance student understanding of computer networking con-
cepts effectively. Chapter V highlights the use of simulation and animation tools
in teaching communication protocols. Chapter VI describes a low-cost labora-
tory infrastructure for enhancing student understanding of packet-forwarding
concepts and theories. Chapter VII examines the use of the tool Ethereal in the
classroom for teaching TCP/IP protocols in a practical way.
Section III: Wireless Networking and Information Security. Section III
consists of three chapters (VIII through X) and provides detailed coverage of
the software and hardware tools, cases, and lab activities designed to enhance
teaching and learning various aspects of wireless networking concepts and in-
formation security risk analysis. Chapter VIII describes a series of wireless
projects for teaching and learning wireless communication networks. Chapter
IX focuses on teaching and learning Wi-Fi networking and propagation mea-
surements using limited resources. Chapter X highlights teaching and learning
information security risk analysis using a teaching hospital model.

xi
Section IV: Teaching and Learning Computer Hardware. Section IV con-
sists of six chapters (XI through XVI) and provides software and hardware
tools, including processor simulator and lab activities, to enhance teaching and
learning various aspects of computer hardware concepts. Chapter XI provides
a practical introduction to input and output ports. Chapter XII describes a set of
PIC-based practical laboratory exercises for teaching and learning computer
hardware concepts. Chapter XIII focuses on teaching computer hardware con-
cepts using PBL theory. Chapter XIV discusses the use of a processor simula-
tor in teaching computer architecture both at introductory and advanced levels.
Chapter XV describes a remotely accessible embedded systems laboratory for
teaching and learning computer hardware. Chapter XVI reports on the devel-
opment and use of a software tool (named LOGIC-Minimiser) for teaching and
learning minimization of Boolean expressions.
Section V: Data Communication Protocols and Learning Tools. Section
V consists of two chapters (XVII and XVIII) and provides detailed coverage
of learning tools and techniques designed to enhance teaching and learning
various aspects of data communication protocols. Chapter XVII provides a
practical introduction to serial protocols for data communications, and Chapter
XVIII describes the use of VMware in teaching and learning contexts.
Target Audience for This Book
Teachers, tutors, and students in schools of business, information technology,
engineering, computer and information sciences, and other related disciplines
will benefit from the use of this book. Moreover, the book will provide insights
and support for both instructors and students involved in training courses in
networking and hardware fundamentals at various vocational training institu-
tions.
How to Use This Book
The innovative open source software and hardware tools and new ideas pre-
sented in the book enable the book to be used by both teachers and students as
a resource to enhance teaching and learning computer networking and hard-
ware concepts in a variety of teaching and learning contexts. Students can also
benefit from the learning aids, such as learning objectives, summary, key terms
and definitions, figures and illustrations, examples and review questions, and
references that are provided in each chapter.

xii
Learning Aids
The book provides the following learning aids:
• Learning Objectives: Each chapter begins with a list of learning objec-
tives that previews the chapter’s key ideas and highlights the key con-
cepts and skills that students can achieve by completing the chapter. Learn-
ing objectives also assist teachers in preparing a lesson plan for a particu-
lar topic.
• Figures and Illustrations: The key concepts in both computer network-
ing and hardware are illustrated using diagrams and screenshots through-
out the book. These illustrations help students to develop a better under-
standing of the key concepts in computer hardware and networking.
• Examples: Various real-world examples have been introduced in the chap-
ters to explain the use of tools and techniques learned from the text.
• Summary: Each chapter provides a brief summary of the contents pre-
sented in the chapter. This helps students to preview key ideas in the chap-
ter before moving on to the next chapter.
• Key Terms and Definitions: Each chapter provides a set of key terms
and their definitions. Both students and teachers can benefit by using the
listing of key terms and definitions to recall key networking and hardware
concepts before and after reading the chapter.
• Review Questions: Each chapter provides a set of end-of-chapter re-
view questions linked to the learning objectives, allowing the teachers to
evaluate their teaching effectiveness. Answers to most of the review ques-
tions can be found in the relevant chapter(s), and hence students are en-
couraged to revisit the relevant sections of the chapter in order to find the
answers. By answering the review questions, students can develop a deeper
understanding of many key networking and hardware concepts and tools.
Teachers and instructors can use the review questions to test their teach-
ing effectiveness and to initiate class discussion.

This book contains contributions from many leading professors and researchers
from around the world in the field of computer networking and hardware con-
cepts. One of the most challenging tasks for the editor was to integrate the
individual submissions from the 26 authors involved (including the editor) into a
coherent book. Toward this end, to enhance the readability of the book and to
make it a useful resource, the editor has introduced some additional material,
including learning objectives, an end-of-chapter summary, and review ques-
tions. The editor maintained close liaison with the contributing authors through-
out the manuscript preparation process. Each chapter was reviewed by two or
more anonymous reviewers and then revised to address the concerns of the
reviewers. While most individual chapter authors were contacted for the revi-
sions, the editor revised some of the chapters. The list of authors who contrib-
uted full chapters to this book is as follows:
• Nurul I. Sarkar, Auckland University of Technology, New Zealand
• Krassie Petrova, Auckland University of Technology, New Zealand
• K. Sandrasegaran, University of Technology, Australia
• Minh Trieu, University of Technology, Australia
• Cecil Goldstein, Queensland University of Technology, Australia
• Karen Stark, Queensland University of Technology, Australia
• Susanna Leisten, Queensland University of Technology, Australia
• Alan Barry Tickle, Queensland University of Technology, Australia
• Kenneth J. Turner, University of Stirling, Scotland
• Anthony P. Kadi, University of Technology, Australia
• David Bremer, Otago Polytechnic, New Zealand
• Trevor M. Craig, Wollongong College, New Zealand
• Wilson Siringoringo, Auckland University of Technology, New Zealand
Contributing Authors
xiii

xiv
• Sanjay Goel, University at Albany, SUNY, and NYS Center for Information
Forensics and Assurance
• Damira Pon, University at Albany, SUNY, and NYS Center for Information
Forensics and Assurance
• David L. Tarnoff, East Tennessee State University, USA
• Maiga Chang, National Science and Technology Program for e-Learning,
Taiwan
• Kun-Fa Cheng, Chih Ping Senior High School, Taiwan
• Alex Chang, Yuan-Ze University, Taiwan
• Ming-Wei Chen, Chih Ping Senior High School, Taiwan
• John Morris, The University of Auckland, New Zealand
• Steve Murray, University of Technology, Australia
• Vladimir Lasky, University of Technology, Australia
• Khaleel I. Petrus, University of Southern Queensland, Australia
• João de Jesus Eduardo Correia, Christchurch Polytechnic Institute of Tech-
nology, New Zealand
• Ricky Watson, Christchurch Polytechnic Institute of Technology, New Zealand

Acknowledgments
I would like to thank each of the chapter authors, without whose
contributions this book would not have been possible. I am indebted
also to the anonymous reviewers for their invaluable time and effort
in reviewing the manuscripts. Their constructive comments and sug-
gestions helped to improve the quality of the book significantly. My
thanks go also to Mr. Michael Taler for providing feedback on Chap-
ter II and to the entire production team at Idea Group Inc. for their
ongoing support. Lastly, but most importantly, to my wife for her pa-
tience, love, and encouragement throughout this project.
Nurul I. Sarkar
xv

Introduction to Computer Networking and Hardware Concepts 1
Copyright © 2006, Idea Group Inc. Copying or distributing in print or electronic forms without written
permission of Idea Group Inc. is prohibited.
Chapter I
Introductionto
ComputerNetworking
andHardwareConcepts
Abstract
This chapter provides an introduction to computer networking and hardware
concepts and highlights the use of software and hardware tools as an aid
to enhance teaching and learning computer networking and hardware
fundamentals. A basic knowledge of network topology, channel access
protocol, network traffic, and networking devices is needed when designing
and implementing a LAN. The term computer hardware refers to the
physical components of a computer system — those that one can see and
touch. The CPU, memory, and input and output devices are the main
components of a computer. To understand the operation of a modern
processor, it is important that the student grasp the basic concepts of
computer hardware.

2 Sarkar
Learning Objectives
After completing this chapter, you will be able to:
• Give an overview of computer networking and hardware fundamentals.
• Draw a block diagram of a computer.
• Discuss the significance of interactive teaching in introductory computer
networking and hardware courses.
• Appreciate the need for software/hardware tools for teaching and learning
various aspects of computer networks and hardware.
Overview of Computer Networking
A computer network consists of two or more computers or other intelligent
devices linked by communication media (e.g., cable or wireless media) to
achieve successful communication. Computer networking is used in many
aspects of our lives, and its applications are proliferating. For example, computer
networks can be found in universities, secondary schools, and colleges, while in
the corporate world, networks link geographically separated offices. Local and
state government offices use computer networks, as do military organizations,
medical facilities, and the Internet.
Computer networks can be categorized as: (1) local area networks (LANs), (2)
metropolitan area networks (MANs), and (3) wide area networks (WANs). The
fundamental differences among LANs, MANs, and WANs are distance cover-
age, transmission speed, media, and error rate. A LAN is a class of computer
network that covers a relatively small geographic area, for example, a room, a
building or a campus. A LAN is owned by a single organization and physically
located within the organization’s premises. IEEE 802.3 Ethernet CSMA/CD
(Carrier Sense Multiple Access with Collision Detection) is an example of a
LAN (IEEE 802.3, 1998). More details about LANs, in general, can be found in
many textbooks (Forouzan, 2003; Keiser, 2002; Stamper, 2001), and LAN design
is discussed in Fitzgerald and Dennis (2002) and Sarkar and Petrova (2005b). A
MAN is a backbone network that links multiple LANs in a large city or a
metropolitan region covering up to 40 km. The IEEE 802.6 Fibre Distributed Data
Interface (FDDI) is an example of a MAN (Comer, 2001; Forouzan, 2004). A
WAN is a class of network that covers a large geographical area (e.g., a country
or a continent). Telephone networks and the Internet are examples of WANs.

How to Design a LAN
To implement a LAN, both hardware and software are required. A network
operating system (NOS), such as Novell NetWare or MS Windows 2003, needs
to be installed on a PC (called the server), and client software is installed on every
PC (called a workstation or client) that is linked to the network. Each workstation
and the server must have a network interface card (NIC). A cable then connects
the NIC to the LAN’s hub or switch.
Table 1 lists the LAN topologies, access protocols, and corresponding network-
ing devices and cables for wired LAN design. In designing and implementing a
LAN, it is important to have a plan for the: (1) network architecture and channel
access protocol (e.g., Ethernet CSMA/CD or token passing), (2) network size
(i.e., number of servers, workstations, printers, etc.), and (3) connecting devices
(e.g., hub-based or switched network).
Figure 1 shows an Ethernet LAN with one file server, 10 workstations, and two
printers using a star physical and logical topology.
Overview of Computer Hardware
A computer is an electronic machine that can process data/information ex-
tremely quickly and accurately. Computer hardware is the visible, physical
component of the computer that we can touch. There are four main components
of a computer system: (1) processor (also called central processing unit, or
CPU), (2) memory, (3) input devices, and (4) output devices. Figure 2 shows a
block diagram of a computer.
Table 1. LAN topologies, access protocols, and networking devices and
associated cables
Topology/Architecture
Channel
Access Method
Device Cable
Physical Bus Logical Bus
Physical Star Logical Bus
Physical Star Logical Star
Physical Star Logical Ring
Physical Ring Logical Ring
Ethernet CSMA/CD
Ethernet CSMA/CD
Ethernet CSMA/CD
Token Passing
Token Passing
-------
Ethernet Hub
Ethernet Switch
Token Ring Hub
------
Coaxial
UTP
UTP
UTP/Optical Fibre
UTP/Optical Fibre

4 Sarkar
The CPU can be thought of as the heart of a computer. Examples of CPUs
include Intel Pentium 4, Motorola M68000, and Zilog Z-80. The memory is used
to store data and instruction. Random access memory (RAM) is an example of
main memory. The input devices are used to enter data (or programs) into the
computer, and output devices are used to display the results. The keyboard and
mouse are common examples of input devices, while the monitor and printer are
common output devices.
The CPU has two main components: (1) arithmetic and logic unit (ALU), and (2)
control unit (CU). The ALU performs all arithmetic, comparison and logical
operations, and the CU controls the processing of instructions and movement of
Figure 1. A server-based Ethernet LAN with 10 PCs and two printers
(physical and logical star topology)
Figure 2. Block diagram of a computer
Switch: some of the switching fabric
Server
Memory
Input
Device
Processor
(CPI)
Output
Device

internal data from one part of the CPU to another. Arithmetic operations include
addition, subtraction, multiplication, and division. Logical operations include
AND, OR, NOT, and Compare. The ALU contains a set of general-purpose
registers called the accumulator. An accumulator is a temporary storage used to
hold data that is used for arithmetic and logical operations. It is also used to hold
results of arithmetic and logical operations. More details about CPUs and
memory can be found in many textbooks (Englander, 2000; Shelly, Cashman, &
Vermaat, 2003).
The CU has several special-purpose registers and their functions are briefly
described below:
• Program counter (PC): The PC holds the address of the next instruction
to be executed.
• Instruction register (IR): The IR holds the actual instruction being
executed currently by the computer.
• Memory address register (MAR): The MAR holds the address of a
memory location.
• Memory data register (MDR): The MDR holds a data value that is being
stored to or retrieved from the memory location currently addressed by the
memory address register.
• Status register (SR): The SR indicates the results of an arithmetic and
logic unit operation. For example: carry, overflow, negative.
Figure 3 shows the main components of a control unit.
Figure 3. Components of a control unit
Components of CU
PC
IR
MAR
MDR
SR
CU = Control Unit
PC = Program Counter
IR = Instruction Register
MAR = Memory Address Register
MDR = Memory Data Register
SR = Status Register

6 Sarkar
The CPU-Memory Interaction
A computer processes and stores data as a series of binary digits called bits. A
bus is a collection of wires or lines used for transferring data and instructions
between the CPU and the main memory; one line for each bit (data and address).
There are three types of CPU buses: (1) address bus, (2) data bus, and (3) control
bus. The address bus is used to select a memory address or location and can be
8-bit, 16-bit, or 32-bit. The data bus is used to carry data or the address of the
data between the CPU and main memory and vice versa. The data bus can be
8-bit, 16-bit, 32-bit, or 64-bit. The control bus is used to carry control signals (e.g.,
READ, WRITE, HALT) to perform specific operations. For example, when the
READ signal is activated (i.e., R/W line is high or 1), the memory performs the
READ operation. Figure 4 illustrates the CPU-memory interaction.
The Fetch-Execute Cycle
Depending on the complexity of each operation (i.e., task), the computer may
take two or more machine cycles in order to complete the task. A machine cycle
consists of both fetch and execution cycles. In the fetch cycle, the CU brings the
program instruction from the memory, decodes it (i.e., translates the instruction
into commands), and then sends the data to the ALU for execution. In the
execution cycle, the ALU performs an operation and then sends the result to the
memory for temporary storage. Figure 5 illustrates the basic concept of the
fetch-execution cycle.
Figure 4. The CPU-memory interaction
CPU
Address Bus
MEMORY
Data Bus
Control Bus

Tools for Teaching Computer
Networking and Hardware Concepts
Computer networking and hardware courses are becoming increasingly popular
in universities, polytechnical institutions, postsecondary colleges, and private
training institutions worldwide because of the high demand for people with
computer networking and hardware skills.
The learning-by-doing approach is an essential component in courses on
computer networking and hardware fundamentals (Abe et al., 2004; Burch,
2002; Comer, 2002; Sarkar, 2005). The view is frequently supported in the
educational literature (Anderson, Reder, & Simon, 1996; Young, 1993) that
students learn computer networking and hardware concepts better if they are
given hands-on practical exercises that illustrate theoretical concepts. Yet,
despite the Chinese adage, attributed to Confucius (551-479 BC), “I hear, I
know. I see, I remember. I do, I understand,” only a limited amount of material
designed to supplement the teaching of computer networking is publicly avail-
able, as searches of the Computer Science Teaching Center Web site (http://
www.cstc.org/)andtheSIGCSEEducationLinkspage(http://sigcse.org/topics/)on
the Special Interest Group on Computer Science Education Web site reveal.
To enable students to appreciate and understand computer networking and
hardware fundamentals, a teaching and learning tool should be Web-based,
portable, modular, configurable, and extensible. Some existing tools for teaching
and learning computer networking and hardware concepts are described next.
Figure 5. Fetch and execution cycle
Control Unit ALU
2. Decode instruction
1. Fetch instruction
3. Get data
4. Perform operation
Primary Memory/RAM

8 Sarkar
Some Existing Tools for Teaching Computer-Networking
Concepts
Both open source and commercial tools are available for building a variety of
network models and visualization of network topologies. We briefly highlight
some of the tools reported in the computer-networking literature that are suitable
for classroom use.
• ns-2 (Fall & Varadhan, 2003): The network simulator ns-2 is a powerful,
text-based simulation software package suitable for performance analysis
and evaluation of computer networks. It is a discrete event simulator
originally developed at Lawrence Berkeley Laboratory at the University of
California, Berkeley, as part of the Virtual InterNetwork Testbed (VINT)
project. The Monarch project at Carnegie Mellon University (Monarch,
2004) has extended the ns-2 by adding support for IEEE 802.11 wireless
LANs.
• OPNET (2004): OPNET is a popular commercial software package
commonly used by researchers and practitioners for modeling and simula-
tion of computer networks. Unlike ns-2, OPNET is menu-driven with an
easy-to-use graphical user interface for rapid model construction, data
collection, and other simulation tasks. As working with the simulator
involves setting up complex experiments, it might be suitable as a learning
environment in advanced networking classes.
• cnet (McDonald, 2004): The cnet network simulator enables experimen-
tation with protocols at the data link, routing, and transport layers in
networks consisting of any combination of WANs and LANs. Although
cnet is being used worldwide in undergraduate networking courses, the
need to prepare a network topology file as the basis of topology visualization
might be a challenging task for beginners.
• JASPER (Turner & Robin, 2001): JASPER (Java Simulation of Proto-
cols for Education and Research) is a protocol simulator that can be used
as an aid to enhance teaching and learning communication protocols. It is
an extensible tool in which students can readily add new protocols.
• WebLan-Designer (Sarkar & Petrova, 2005a): WebLan-Designer is a
Web-based tool for interactive teaching and learning both wired and
wireless LAN design. Using the “modeling” page, students can experiment
with a variety of LAN topologies and channel access protocols. Students
can also test their knowledge of various aspects of LAN design by using
two interactive quizzes. Each quiz consists of a set of more than 25 multiple-
choice questions, each with four possible answers. At the end of each quiz

session, the system displays the total score, which allows students to assess
their prior knowledge about LAN design. The system provides a friendly
environment for interactive quiz management. This is particularly useful for
the teacher to update quizzes on a regular basis.
• DlpSim (King, 2004): DlpSim (data link protocol simulator) may be
suitable for classroom use to enhance teaching protocols through simula-
tion. However, its emphasis is exclusively on data link layer protocols.
• WebTrafMon (Hong, Kwon, & Kim, 1999): The WebTrafMon is a
Web-based system for network analysis and traffic monitoring. However,
the system focuses exclusively on network analysis and traffic monitoring,
and the system needs to be configured and set up for use in a teaching
environment.
• NetMod (Bachmann, Segal, Srinivasan, & Teorey, 1991): The NetMod
is a network modeling tool which uses some simple analytical models,
providing designers of large, interconnected local area networks with an in-
depth analysis of the potential performance of such systems. The tool can
be used in university, industrial, or governmental campus networking
environments and might serve as a useful demonstration in the classroom.
• iNetwork (see Chapter III): iNetwork is an interactive software tool for
teaching and learning data communication networks. iNetwork allows
students to assemble and build customised networks using networking
devices such as workstations, switches, routers, DNS servers, and DHCP
servers. Students can simulate data communication between networking
devices and identify and troubleshoot problems in their custom-built net-
works. Through experimenting with key parameters, students gain insights
into the key concepts of communication network design and analysis.
Some Existing Tools for Teaching Computer Hardware
Concepts
A number of open source tools exist for modeling and simulation of computer
hardware and processors. We briefly review some existing tools, suitable for
classroom use, that have been reported in the literature.
• Logisim (Burch, 2002): Logisim is a software tool for logic circuit design
and simulation which is suitable for classroom use. It has a graphical user
interface, which helps students to gain a better understanding of the design
and simulation of logic circuits. Logisim is a Java application and can be run
on both Windows and UNIX workstations.

10 Sarkar
• DigitalWorks 3.0 (Anonymous, 2006): DigitalWorks is similar to Logisim
inthatitprovidesagraphicaltoolboxinterfaceforcomposingandsimulating
logic circuits.
• WinLogiLab (Hacker & Sitte, 2004): WinLogiLab is an interactive
Microsoft-Windows-compatible computerized teaching suite suitable for
classroom use as an aid to enhance teaching and learning digital logic design
concepts. It provides a set of interactive teaching aids to approach the
basics of combinatorial and sequential digital circuit design. WinLogiLab is
targeted toward introductory digital design courses in electrical and com-
puter engineering curricula.
• Web-based processor simulator (see Chapter XIV): This is a Web-
based modular and extensible processor simulator designed as an aid to
teaching and leaning computer architecture and hardware concepts. Stu-
dents in advanced classes are able to incorporate new modules by simply
writing new Java classes and adding them to a configuration file, which
specifies the new modules’ connections to other modules. The modular
structure means that it can be used for both introductory computer
organization and more advanced processor architecture courses.
• LOGIC-Minimiser (see Chapter XVI): LOGIC-Minimiser is an inter-
active software tool suitable for classroom use as an aid to enhance
teaching and learning Boolean expression minimization. It serves as both
student-centered, self-paced learning and a classroom demonstration tool.
LOGIC-Minimiser is easy to use and can be run under MS-DOS/Windows
machines.
• Picocontroller simulator (Collier, 2003): This is an interactive applet in
a Web page for PIC16F84 picocontroller simulation. It displays the source
program, RAM locations, and the contents of special function registers.
Users can step through programs observing the memory changes to
facilitate an understanding of the operation of the picocontroller.
Outline of the Remainder of This Book
Chapter II. Motivating students to learn local area network (LAN) design can
be difficult since students find the subject dry, technical, and boring. To
overcome this problem, the authors have developed a Web-based software tool
named WebLan-Designer for interactive teaching and learning both wired and
wireless LAN design. Chapter II reports on the development and use of
WebLan-Designer as an aid to enhance teaching and learning LAN design. It

also highlights the educational benefits of using WebLan-Designer in classroom
settings.
Chapter III. A country or a nation would be immobilized without its computer
and data communication networks. Computer networking courses are being
offered by not only universities and tertiary institutions but also many technical
colleges and secondary schools worldwide. The cost associated with purchasing
networking devices and equipment to enable students to gain practical experi-
ence in setting up a customised network can be significant. Therefore, network-
ing fundamentals are taught by a combination of textbooks and lecture-only
methods in many schools and publicly funded tertiary institutions. Chapter III
describes the development and use of an interactive learning tool called
iNetwork for teaching and learning computer communication networks. iNetwork
provides an environment in which students can experiment with different
network configurations and gain hands-on learning experience in computer and
data communication networks without the need for expensive equipment.
Chapter IV. Teaching computer networking in large classes (e.g., 350-400
students) can be challenging compared to teaching in small classes of 15-20
students. This is partly because of the difficulty in motivating students to learn
technical and rather dry subjects and also because of the lack of interaction
among the students in large classroom settings. Network simulators allow
students to build a network dynamically by placing network devices as icons on
a screen and connecting them. The graphical display and animation brings more
interactivity and liveliness in the classroom, and consequently it is easier for
students to engage in learning computer networking more effectively. Chapter
IV focuses on the use of a network simulator in large classroom settings to
enhance teaching and learning computer-networking fundamentals.
Chapter V. Communication protocols are essential components of computer
and data communication networks. Therefore, it is important that students grasp
these concepts and become familiar with widely used protocols. Unfortunately,
communication protocols can be complex and their behavior difficult to under-
stand. In order to learn about protocols, a student therefore needs a more
controlled and constrained environment. Chapter V describes the development
and use of a protocol animator for teaching and learning communication
protocols.
Chapter VI. Teaching packet-forwarding theories and concepts in a practical
way to undergraduate students requires both a teaching and learning framework
and a laboratory infrastructure. Creating a teaching and learning framework in
which students can develop a deeper knowledge and understanding of abstract
concepts is not a simple task. In addition to teaching materials, the teacher
requires a clear idea about learning theories and issues: (1) What is learning? (2)
What is knowledge? and (3) How do students go about learning? Chapter VI

12 Sarkar
describes a low-cost laboratory infrastructure for teaching and learning packet-
forwarding theories and concepts. The framework is learner-centred and is
focused on learning experiences in both the classroom and the laboratory. The
laboratory-based activities form a critical component of the overall framework.
Chapter VII. Students can learn data communication and networking protocols
better if they are given hands-on practical exercises, in which the concept of
abstract protocols can be linked to real-world communication concepts. For
example, one can learn about address resolution protocol (ARP) by lectures and
readings. However, by examining actual ARP traffic from a sample of packets,
identifying their behavior, and performing troubleshooting, students gain first-
hand experience that cannot be gained through theoretical study. One of the
challenges that networking educators are facing is the problem of giving students
an “up close and personal” interaction with protocols that are so heavily
immersed in theory. Chapter VII emphasises that real experience with network
protocols is crucial to effective student learning.
Chapter VIII. Due to the rapid developments in wireless communication and
networking technologies and the high demand for wireless networking skills in
the industry worldwide, wireless communication and networking courses are
becoming increasingly popular in universities, polytechnics, and private training
institutions around the globe. Unfortunately, wireless communication and net-
working is a challenging subject to teach in a meaningful way because many
students appear to find the subject technical and rather boring. To overcome this
problem, the authors introduce a set of new projects in order to provide students
of wireless communication and networking with a hands-on learning experience.
The projects are suitable for classroom use in introductory wireless networking
courses.
Chapter IX. Wi-Fi networking has been becoming increasingly popular in recent
years, both in terms of applications and as the subject of academic research
papers and articles in the IT press. It is important that students grasp the basic
concepts of both Wi-Fi networking and wireless propagation measurements.
Unfortunately, the underlying concepts of wireless networking often intimidate
students with their apparently overwhelming complexity, thereby discouraging
the students from learning in-depth this otherwise exciting and rewarding
subject. Chapter IX provides a tutorial on Wi-Fi networking and radio propaga-
tion measurements using wireless laptops and access points. Various hands-on
learning activities are also discussed.
Chapter X. There is a strong need for information security education, which
stems from the pervasiveness of information technology in business and society.
Both government departments and private industries depend on information
systems, as information systems are widespread across all business functions.
Disruption of critical operational information systems can have serious financial

impacts. According to the CSI/FBI report, losses from security breaches have
risen rapidly in recent years and exceeded $200 million in 2003. The information
security field is very diverse and combines disciplines such as computer science,
business, information science, engineering, education, psychology, criminal
justice, public administration, law, and accounting. The broad interdisciplinary
nature of information security requires several specialists to collaboratively
teach the curriculum and integrate different perspectives and teaching styles into
a cohesive delivery. Chapter X presents a pedagogical model based on a
“teaching hospital” concept that addresses the issues introduced above. By using
a specific information risk analysis case, the chapter highlights the basic concept
of the teaching hospital and its application in teaching and learning contexts.
Chapter XI. It is important that students grasp the basic concepts of commu-
nication between a processor and external devices, and become familiar with
tools that are available to implement such systems. Chapter XI describes the
operation of the processor bus and explains how I/O devices are connected to
it. It also discusses advanced I/O techniques and how the operating systems use
I/O to access a computer’s resources.
Chapter XII. Computer hardware, number systems, CPU, memory, and I/O
(input/output) ports are topics often included in computer science, electronics,
and engineering courses as fundamental concepts involved in computer hard-
ware. We believe that students learn computer hardware fundamentals better if
they are given practical learning exercises that illustrate theoretical concepts.
However, only a limited range of material designed specifically to supplement the
teaching of computer hardware concepts is publicly available. Chapter XII
describes a set of PIC-based projects that give students a hands-on introduction
to computer hardware concepts and are suitable for classroom use in under-
graduate computer hardware courses.
Chapter XIII. Students often get a good score in written exams but fail to apply
their knowledge when trying to solve real-world problems. This applies particu-
larly to computer hardware courses in which students are required to learn and
memorize many key terms and definitions. Also, teachers often find it difficult
to gauge students’ progress when teaching computer hardware fundamentals
courses. These problems are related to the learning process, so it is necessary
to find an appropriate instructional model to overcome these problems. Chapter
XIII describes a Web-based tool called an assistant tool based on problem-based
learning (PBL) theory that not only assists instructors in teaching computer
hardware fundamentals but also overcomes the above-mentioned problems.
Chapter XIV. Computer architecture educators are constantly looking for
modular tools that allow processors to be configured in a transparent way; the
visualization enables rapid verification that modules have been connected in the
desired manner. Thus, simple experiments which demonstrate, for example, the

14 Sarkar
effect of different cache organizations are readily configured by instructors or
students. Advanced computer architecture students will also be able to add
experimental capabilities (in the form of new modules or modifications to existing
ones) and perform simple experiments to assess their effect on processor
performance. Chapter XIV discusses the development and use of a processor
simulator in teaching computer architecture at both introductory and advanced
levels. It is written in Java, which allows it to be easily embedded in other Web-
based course materials and run anywhere.
Chapter XV. To teach modern embedded systems, including operating systems,
in a meaningful way, a moderately sophisticated processor is required to
demonstrate many key concepts, such as multitasking, multithreading, structured
and abstracted hardware management layer, communications utilising various
protocols over network interfaces, and memory resident file systems. Unfortu-
nately, high-end 32-bit embedded systems processors capable of supporting
these facilities are expensive compared to conventional 8-bit and 16-bit targets,
and it is not feasible to acquire a large number of them to house in a laboratory
in an effort to enable practical exercises for over 100 students. Chapter XV
describes the development and use of a remotely accessible embedded systems
laboratory that uses a small number of 32-bit development systems and makes
them available to students over the Internet.
Chapter XVI. Boolean algebra, minimization of Boolean expressions, and logic
gates are often included as a subject in electronics, computer science, informa-
tion technology, and engineering courses as computer hardware and digital
systems are a fundamental component of IT systems today. We believe that
students learn minimization of Boolean expressions better if they are given
interactive practical learning activities that illustrate theoretical concepts. Chap-
ter XVI describes the development and use of a software tool (named LOGIC-
Minimiser) as an aid to enhance teaching and learning minimization of Boolean
expressions.
Chapter XVII. Serial communication is used as a long-distance computer
system interface due to its reliability and cost effectiveness. All information
pertaining to the delivery of a message must be contained within a single stream
of bits. In order to implement a serial data communication system, a well-defined
set of rules called a protocol must exist to specify the placement and purpose of
every bit sent across the link. Chapter XVII provides a practical introduction to
serial protocols for data communications. It shows how a protocol analyser can
be used in examining the frames of the data link layer and the packets of the
network layer.
Chapter XVIII. Providing a dedicated lab to each group of students in order to
gain hands-on learning experience is not always possible due to budget and space
constraints. For example, in a class of 20 students, each student requires at least

three computers with each computer capable of running three operating systems,
such as UNIX, Linux, and Windows Server 2003. This requires a large computer
laboratory with 60 computers in total. In addition, it is difficult to manage the
laboratory to accommodate students from other classes. For example, once one
class leaves the laboratory, another class of 20 students needs to start immedi-
ately, with each person configuring Windows Server 2003 Active Directory on
four computers. This requires another large computer laboratory with eighty
computers. Chapter XVIII presents VMware as a teaching and learning tool to
overcome the problems mentioned above. Under the VMware system, students
do not require administrative privileges on physical machines. Consequently,
they have complete freedom to experiment within their own virtualised environ-
ments.
Conclusion
Because of the high demand for people with computer networking and hardware
skills worldwide, computer networking and hardware courses are becoming
increasinglypopularinbothtertiaryandprivatetraininginstitutions.Unfortunately,
motivating students to learn computer networking and hardware concepts is often
difficult because students appear to find the subject technical and rather dry.
Interactive teaching and learning using software/hardware tools is an attractive
solution to the problem of motivating students to learn computer networking and
hardware fundamentals. This chapter describes the basic concepts of computer
networking and hardware fundamentals and highlights various tools for interac-
tive teaching and learning computer networking and hardware concepts. It also
provides an outline of the remainder of the book.
Summary
Computer networks can be classified as local area networks, metropolitan area
networks, and wide area networks. Each class of network has certain charac-
teristics that make it suitable for certain networking applications. A basic
knowledge of network topology, channel access protocol, network traffic, and
networking devices is needed when designing and implementing a LAN.
The term computer hardware refers to the physical components of a computer
system — those that one can see and touch. The CPU, memory, and input and

16 Sarkar
output devices are the main components of a computer. To understand the
operation of a modern processor, it is important that the student grasp the basic
concepts of computer hardware. An overview of computer networking and
hardware concepts is presented, and various tools for interactive teaching and
learning computer networking and hardware essentials are highlighted.
Key Terms and Definitions
DHCP: DHCP stands for dynamic host configuration protocol. It is often used
to dynamically assign IP addresses to hosts.
DNS: DNS stands for domain name system. It is a service used to map
hostnames onto IP addresses and allow for resolution of hostnames to IP
addresses.
Ethernet: A popular LAN technology that uses a shared channel and the
CSMA/CD access method. Basic Ethernet operates at 10 Mbps, Fast
Ethernet operates at 100 Mbps, and Gigabit Ethernet operates at 1,000
Mbps.
Hub: A networking device that interconnects two or more workstations in a star-
wired local area network and broadcasts incoming data onto all outgoing
connections. To avoid signal collision only one user can transmit data
through the hub at a time.
LAN: LAN stands for local area network. A class of computer network suitable
for a relatively small geographic area, for example, a room, a building, or
a campus. A LAN is owned by a single organization and physically located
within the organization’s premises. Ethernet is the most popular LAN
architecture.
Logical topology: This refers to the way the data is sent through the network
from one computer (or device) to another.
MAN: MAN stands for metropolitan area network. A MAN is a backbone
network that links multiple LANs in a large city or a metropolitan region.
NIC: NIC stands for network interface card. It is the hardware interface that
provides the physical link between a computer and a network.
NOS: NOS stands for network operating system. It is a complex set of computer
programs that manage the common resources of a local area network. In
addition, NOS performs the standard operating system services. Examples
are NetWare, Linux, and MS Windows 2003.
Optical fibre: A type of cable which consists of one or more glass or plastic fibre
cores inside a protective cladding material, covered by an outer plastic PVC

jacket. Signal transmission along the inside fibres is accomplished using
light pulses. The optical fibre cable is characterised by an extremely large
data-carrying capacity. Optical fibre is used for undersea cables and for
countrywide telecommunications backbones.
Peer-to-peer network: A class of network in which a computer can commu-
nicate with any other networked computers on an equal or peer-like basis
without going through an intermediary, such as a server or a dedicated host.
Physical topology: This refers to the way computers and other devices are
connected within the network physically.
Protocol: A protocol is a collection of rules for formatting, ordering, and error-
checking data sent across a network.
Switch: Unlike a hub, a switch allows multiple users to communicate simulta-
neously in order to achieve a higher throughput.
WAN: WAN stands for wide area network. A WAN covers a large geographical
area (e.g., a country or a continent). Telephone networks and the Internet
are examples of WANs.
Workstation: An end-user computer that has its own CPU and is used as a
client to access another computer, such as a file server.
Review Questions
1. What is a network? Discuss the basic difference between a local area
network and a wide area network.
2. List and describe three important components of a communication system.
3. Define the following networking terms: LAN, MAN, WAN, protocol, peer-
to-peer network, and server-based network.
4. You are given the following components: one server, 10 PCs, and one
printer. Draw a diagram to show how the above components can be
connected to construct a LAN using: (a) bus topology, (b) ring topology, and
(c) star topology. Use a hub/switch when appropriate.
5. Discuss the importance of interactive teaching in introductory computer
networking and hardware courses.
6. List and describe four main components of a computer system.
7. List and describe two main components of a central processing unit.
8. Describe the function of address, data, and control buses.
9. Draw a diagram to illustrate the interaction between a CPU and the main
memory.

18 Sarkar
10. Discuss the significance of software/hardware tools in teaching and
learning computer networking and hardware concepts.
11. List and describe three software tools suitable for classroom use to
enhance teaching and learning computer-networking concepts.
References
Abe, K., Tateoka, T., Suzuki, M., Maeda, Y., Kono, K., & Watanabe, T. (2004).
An integrated laboratory for processor organization, compiler design, and
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Anderson, J. R., Reder, L. M., & Simon, H. A. (1996). Situated learning and
education. Educational Researcher, 25(4), 5-11.
Anonymous. (2006). Digital Works. Retrieved January 5, 2006, from http://
www.spsu.edu/cs/faculty/bbrown/circuits/howto.html
Bachmann, D. W., Segal, M. E., Srinivasan, M. M., & Teorey, T. J. (1991).
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Collier, M. (2003). A picocontroller training simulator in a Web page. Interna-
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Comer, D. E. (2001). Computer networks and Internets with Internet appli-
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Comer, D. E. (2002). Hands-on networking with Internet technologies.
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Englander, I. (2000). The architecture of computer hardware and systems
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Hacker, C., & Sitte, R. (2004). Interactive teaching of elementary digital logic
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Hong, J. W.-K., Kwon, S.-S., & Kim, J.-Y. (1999). WebTrafMon: Web-based
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puter Communications, 22(14), 1333-1342.
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Keiser, G. (2002). Local area networks (2nd
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January 5, 2006, from www.cee.hw.ac.uk/~pjbk/dlpjava
McDonald, C. (2004). The cnet network simulator (v2.0.9). Retrieved January
5, 2006, from www.csse.uwa.edu.au/cnet/
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20 Sarkar
Section II
Teaching and Learning
Computer Networking

WebLan-Designer 21
Chapter II
WebLan-Designer:
A Web-Based Tool to
Enhance Teaching and
Learning Wired and
Wireless LAN Design
Krassie Petrova, Auckland University of Technology, New Zealand
Abstract
It is somewhat difficult to motivate students to learn both wired and wireless
local area network design because students find the subject technical, dry
when delivered in class, and rather boring. This chapter introduces the
case of a Web-based tool for class demonstration as well as modelling LAN
design. The background of the case is presented and is followed by a review
of some existing tools for network simulation and modelling. After
introducing the learning theories and concepts (e.g., experiential learning
and constructivism) relevant to the tools’ pedagogical value, the chapter
describes the architecture and components of WebLan-Designer. The main
benefits of using WebLan-Designer are discussed in the light of educational
theories, and their validation is supported by a summary of comments
received. The chapter concludes with remarks on the strengths and
weaknesses of WebLan-Designer and its future development.

22 Sarkar & Petrova
Learning Objectives
After completing this chapter, you will be able to:
• Discuss the usefulness of WebLan-Designer in teaching and learning
contexts.
• Use WebLan-Designer in both face-to-face and distance learning environ-
ments for teaching and learning LAN design.
• Verify the solutions to LAN design exercises using WebLan-Designer.
• Suggest further enhancements to WebLan-Designer.
Introduction
It is somewhat difficult to motivate students to learn both wired and wireless local
area network design because students find the subject technical, dry when
delivered in class, and rather boring. Educators have experimented with different
approaches to alleviate this problem. Examples include computer-assisted
learning packages (Diab & Tabbara, 1995), game-based simulation (Shifroni &
Ginat, 1997), approaches based on the constructivist paradigm (Chen, 2003),
experiential learning (R. K. C. Chang, 2004), and learning research techniques
such as the phenomenographical approach (Berglund, 2003).
This chapter introduces the case of a Web-based tool for class demonstration as
well as modelling LAN design. The motivational background of the case is
presented in the next section and is followed by a review of some existing tools
for network simulation and modelling. After introducing the learning theories and
concepts (e.g., experiential learning and constructivism) relevant to the tools’
pedagogical value, the chapter describes the architecture and components of
WebLan-Designer. The main benefits of using WebLan-Designer are discussed
in the light of educational theories, and their validation is supported by a summary
of comments received. The chapter concludes with remarks on the strengths and
weaknesses of WebLan-Designer and its future development.
Background and Motivation
LANs are often included as a topic in computer science, information technology,
engineering, and business courses as LANs are a fundamental component of IT

WebLan-Designer 23
systems today. We believe that students learn LAN design better if they are
given interactive practical exercises that illustrate theoretical concepts. There is
still very little material publicly available to supplement the teaching of LAN
design, as a searches of the Computer Science Teaching Center Web site (http:/
/www.cstc.org/) and the SIGCSE Education Links page (http://sigcse.org/
topics/) on the Special Interest Group on Computer Science Education Web site
reveal. Even less course material is available on wireless networking and related
topics. The need for learner support in the areas of computer networking is
especially strong (Petrova, 2002).
We strongly believe, as do many others (Abe et al., 2004; Bhunia, Giri, Kar,
Haldar, & Purkait, 2004; Garcia & Alesanco, 2004; Hacker & Sitte, 2004), that
students learn more effectively from courses that involve them in interactive
learning activities. The theoretical underpinnings of this approach come from
two theories of learning: experiential learning and constructivism. First, the
hands-on learning experience is derived from learning which involves observa-
tion and experimentation and aims to help students develop skills in testing out
different approaches to completing a project (Kolb, Boyatzis, & Mainemelis,
2000). Secondly, as students make their way through the basic framework of
pre-supplied content-related constructs, they are given the opportunity to
develop and reorganize their own concepts and ideas. Learning occurs not by
absorption but through the construction of students’ own knowledge in authentic
context (Chen, 2003).
Computer networking is a particularly challenging subject to learn and to teach
in a meaningful way; students may find the subject technical and rather dry when
presented. A team of Auckland University of Technology-based researchers
developed a Web-based tool called WebLan-Designer, aiming to provide stu-
dents with an interactive learning experience in LAN design. A teacher involved
in an introductory networking course might be able to use WebLan-Designer in
the classroom as a demonstration to enhance the lecture environment. Students,
on the other hand, can use the system to complete networking assignments and
verify (interactively and visually) the solutions to LAN design exercises and in-
class tasks. WebLan-Designer can be accessed at any time either through an
intranet or the Internet. In addition to enhancing classroom teaching by including
an element of online learning, WebLan-Designer also provides online support for
off-campus students and enhances learning by engaging them in a flexible,
learner-centered manner.
LAN design concepts are described in many textbooks (Bing, 2002; Dornan,
2002; Palmer & Sinclair, 2003), and Web-based tools are discussed extensively
in the computer networking literature (Kofke & Mihalick, 2002; Rokou, Rokos,
& Rokou, 2003; Sitthiworachart & Joy, 2003). In the following section we briefly
review various existing software tools related to the proposed system described
in this chapter.

24 Sarkar & Petrova
Some Existing Tools: A Review
Various tools and simulators (both open source and commercial) are available for
building LAN models (X. Chang, 1999; Sanchez & Manzoni, 2001; Zheng & Ni,
2003). However, these often powerful systems can have a steep learning curve,
and while excellent for doing an in-depth performance evaluation of LANs, the
simulated networking environment created is typically far more detailed than is
necessary for introduction to fundamental concepts. Some of the tools which are
reported in the networking literature are described below.
• NetMod (Bachmann, Segal, Srinivasan, & Teorey, 1991): NetMod is
a network modelling tool which uses simple analytical models to provide
designers of large, interconnected LANs with an in-depth analysis of the
potential performance of these systems. The tool can be used in university,
industrial, or governmental campus networking environments, comprising
thousands of computer sites. NetMod is implemented in combination with
the easy-to-use software (HyperCard, Excel).
• The Layer-Module set (Diab & Tabbara, 1995): This teaching tool for
computer network systems includes graphical animation and simulation of
the functions of a network. The environment provides textual information
on the seven OSI layers, supplemented with figures, examples and demon-
strations, and multiple-choice questions. Protocol simulation is used; for
example, the shortest path first and network flow using graph theory.
• WebTrafMon (Hong, Kwon, & Kim, 1999): The WebTrafMon is a
Web-based system for network analysis and traffic monitoring. It provides
monitoring and analysis capabilities not only for traffic loads but also for
traffic types, sources, and destinations. Using a Web browser, users can
monitor traffic statistics and review traffic history.
• ns-2 (Fall & Varadhan, 2003): Ns-2 (network simulator) is a powerful
text-based simulation software package suitable for performance analysis
of computer networks.
• Network Intelligence (Nieuwelaar & Hunt, 2004): Network Intelli-
gence (NI) provides an easy way to view complex traffic patterns in a wide
area networking environment. NI can perform simulations of network
topologies using actual gathered data as opposed to arbitrary data.
• cnet (McDonald, 2004): The cnet network simulator enables experimen-
tation with various data link, network, routing, and transport networking
protocols in networks consisting of any combination of wide area networks
(WANs) and LANs. As a learning tool, cnet has been used worldwide in
undergraduate networking courses.

WebLan-Designer 25
• LAN-Designer (Sarkar & Lian, 2003): LAN-Designer is a prototype
software tool for wired LAN modelling. The software is simple and easy
to use and can be used either in the classroom or at home to enhance
teaching and learning of some aspects of LAN design. However, the
current version of LAN-Designer has very limited features and requires
significant improvement.
• WLAN-Designer (Sarkar, 2004): WLAN-Designer is a Web-based
software tool for wireless LAN modelling (still a prototype). The software
is easy to use and can be accessed either from an intranet or through the
Internet to enhance learning and teaching of various aspects of wireless
LAN design. As LAN-Designer, the current version of WLAN-Designer
requires improvement.
WebLan-Designer, which we describe in the next section, has its own
unique features, including the integration of wired and wireless LAN
design, simplicity, ease-of-use, and a Web-based interactive system.
WebLan-Designer Architecture
and Components
Figure 1 illustrates the three-tier client-server architecture approach used in
implementing the system.
The components of WebLan-Designer are shown in Figure 2. The system
consists of two parts: (1) wired LAN design and (2) wireless LAN design. Both
parts of WebLan-Designer have the following main components:
Figure 1. Architecture of WebLan-Designer
Internet
Web browser
Web server
WebLan-Designer
Database

26 Sarkar & Petrova
• Tutorial: A step-by-step guide designed to take the student through a set
of tasks related to the type of network studied, aiming to enhance the
student’s knowledge and understanding of various aspects of LAN design.
Each tutorial includes self-assessment both at commencement and after
completion.
• Quiz: Students can test their knowledge on both wired and wireless LAN
design at any time by using the two interactive quizzes. Each quiz consists
of a set of 50 multiple-choice questions with four possible answers, and
each question is designed to cover a key concept of LAN design. At the end
of a quiz session, the system displays the total score, which allows the
student to assess his or her knowledge about LAN design. This also allows
the teacher to gauge students’ prior knowledge; for example, how much
students already knew about LAN design before starting the course. As
students use WebLan-Designer’s learning resources, such as LAN mod-
elling and networking key terms and definitions, to learn about some aspects
of LAN design, it might be useful to be able to see the impact of WebLan-
Designer on students’ learning about LAN design. This can be achieved by
comparing the total scores obtained from two quiz sessions: (1) before and
(2) after using the WebLan-Designer learning resources.
• Modelling: It provides an interactive and easy way to develop a variety of
LAN models. Using the “modelling” page of WebLan-Designer, students
Figure 2. Components of WebLan-Designer
WebLan-Designer
Wired LAN
Interactive Quiz
Tutorial
Modelling
Key terms
Scenarios
Review questions
Wireless LAN
Interactive Quiz
Tutorial
Modelling
Key terms
Scenarios
Review questions

WebLan-Designer 27
can experiment with LAN topologies and channel access protocols to
enhance their knowledge and understanding of LAN design. Table 1 lists
the supported topologies and access methods.
Figure 3 shows a screenshot of a modelling page of WebLan-Designer. An
infrastructure wireless LAN is modelled, including 10 workstations, eight
personal digital assistants (PDAs), and two printers.
• Key terms: The key terms and definitions of various topics related to both
wired and wireless networking are summarized in these pages. Examples
of key terms related to LAN design include: bus, star, and ring physical
topologies, logical topology, channel, channel access protocol, CSMA/CD,
Table 1. Topologies and access protocols
Topology/Architecture Channel access method
Wired LAN
Physical Bus Logical Bus
Physical Star Logical Bus
Physical Star Logical Star
Physical Ring Logical Ring
Physical Star Logical Ring
Ethernet CSMA/CD
Token Passing
Wireless LAN
Ad Hoc Network
Infrastructure Network
CSMA/CA
Figure 3. A screenshot of a modelling page

28 Sarkar & Petrova
token passing, workstation, file server, hub, switch, and UTP Cat 5e.
Examples of key terms related to wireless LANs include: ad hoc network,
infrastructure network, PCMCIA card, access point, wireless channel,
CSMA/CA, OFDM, modulation, line of sight, direct sequence spread
spectrum (DSSS), and frequency-hopping spread spectrum (FHSS).
• Scenarios: This feature allows students to examine example backbone
networks based on small business and corporate case scenarios. By
observing an integrated LAN which spans over multiple floors on two or
more buildings (close or at a distance), students can enhance their
knowledge and understanding about campus, small business, and corpo-
rate-wide LAN design. Two scenario examples are shown in Table 2.
• Review questions: The review questions in each part serve as an
extension of the quiz and modelling tasks. Examples include: What layer of
the OSI model is concerned with turning binary code into a physical signal?
and What type of propagation is used by low-frequency radio waves
traveling close to the Earth? The review questions broaden the scope of the
system as they refer to knowledge gained through other activities, such as
lectures or independent reading. We felt that adding a suggested answer
would serve the purposes of learning better than leaving the questions
unanswered.
WebLan-Designer is currently installed on a Web server at Auckland Univer-
sity of Technology (AUT) and is being tested for performance and robustness.
The database-driven implementation is based on the use of PHP and MySQL and
involves a combination of static and dynamic Web pages. Two examples of the
models that the modelling engine creates are shown in Figure 4.
Table 2. Scenario examples
A wired network scenario A wireless network scenario
Two of the university departments are about to
be rehoused and jointly need to install a new
computer laboratory. This laboratory will
occupy two adjacent rooms, with each room
containing 40 PCs. The requirements are: (1)
Each laboratory must be capable of operating
independently. It should be possible to disable
the network in each room separately and at a
single point. (2) The two laboratories should be
capable of being combined for use with large
classes. (3) Each laboratory needs to have its
own Windows 2003 server. Both laboratories
will need to have access to a Linux server,
which they will share.
Pizza House wants to attract more customers
to its pizza parlor in King Street and has
decided to offer a Hotspot Internet Coupon
(Hroup) with every pizza ordered on the spot.
One Hroup gives a 30-minute free Internet
access to any customer who has ordered a
pizza and has a wireless-enabled PDA, a
laptop, or a mobile phone that can access the
Wi-Fi hotspot. The coupon expires if not used
within 1 hour of the purchase. Pizza House has
signed a deal with Broad Bush (a local ISP) to
obtain from them cheap broadband (wireless)
Internet access and use it to offer to Hroup
holders.

WebLan-Designer 29
Teaching and Learning Aspects of
Using WebLan-Designer
For simplicity and ease of use, WebLan-Designer has a graphical user interface
(GUI). The GUI is not only user-friendly but self-explanatory.
Let us briefly highlight the value of WebLan-Designer and how we use it in
teaching and learning contexts. At AUT, the authors teach various aspects of
networking and LAN design, including wireless networks, across three different
programmes: (1) bachelor of business, (2) bachelor of computer and information
sciences, and (3) diploma in IT classes. In line with the observation made by other
authors, for example, Berglund (2003), our experience shows that at times it is
quite difficult to motivate students to learn about wired and wireless LAN design
using the traditional lecture-only method. Students find the topic full of technical
jargon, rather dry when delivered in lecture, and even boring.
Figure 4. (a) A model of a wired LAN (Ethernet); (b) a model of a wireless
LAN (ad hoc)
(a) (b)

30 Sarkar & Petrova
To make the lessons more interesting and to encourage students’ participation
in class, we use WebLan-Designer as an integral part of two 2-hour sessions; for
example, the first session might be based on wired LANs and the second session
on wireless LANs. In the classroom, students are asked to design a server-based
LAN on paper. After a prescribed period of time (e.g., 15 minutes), we introduce
WebLan-Designer to the students and do a walk-through with them to verify
(visually and interactively) their solutions and to learn more about server-based
LAN design. The interactive quizzes, review questions, and key term definitions
are also being used, complementing the modelling task.
In addition to classroom use, the students can access WebLan-Designer from
home and work on exercises and tutorials in their own time and at their own pace.
Thus the tool not only enhances lectures by including an element of online
learning but also provides off-campus online support for students. This is
especially important for students taking courses in a flexible mode, combining
face-to-face classes with self-directed online learning. Figure 5 shows sche-
matically two suggested study guidelines (wired LANs).
As discussed earlier, teaching networking concepts without the ability to engage
students in some practical work makes networking classes dry and boring and
does not motivate students. Consequently, the tool described here attempts to
provide a space for experimentation and knowledge construction, building on
findings in the literature on experiential learning (Kolb, Boyatzis, & Mainemelis,
2000; Kolb & Kolb, 2004) and the constructivist approach to teaching and
Figure 5. A suggested sequence of study
Start Start
Or
Quiz - Wired LAN
Key Terms
Key Terms
LAN Modelling
LAN Modelling
LAN design exercises
LAN design exercises
Scenario-based design
Scenario-based design
Quiz - Wired LAN
Verify
Verify

WebLan-Designer 31
learning using computer-based tools (Chen, 2003; Resnick, 2002). Summarizing
the findings of a large body of research in experiential learning, Kolb et al. point
out that learners from a nontechnical background such as business and manage-
ment tend to learn better when engaged in “concrete experimentation” and
“active experimentation.” With regard to teaching networking, Chen suggests
that constructivism could provide a sound theoretical foundation for teaching
given the complexity of the domain. We believe that the tool described in this
chapter offers educational benefits aligned with the view that students today
need to learn actively and independently, “with the teacher serving as consultant,
not chief executive” (Resnick, 2002).
Firstly, the tool is easy to use and navigate and is accessible through the Internet.
Therefore, it is suitable for a distance learning (off-campus) environment. The
user access to the system can be restricted through a login/password to comply
with additional requirements or constraints. Secondly, the learner is engaged in
a broad and dynamic learning experience. For example, the modelling function
provides a simple and easy way to develop a variety of network configurations,
and students can experiment with LAN topologies and channel access protocols
and thus gain a better understanding of LAN design. In addition to LAN
modelling, eight business case scenarios and suggested solutions, which provide
real-world examples to students about the organization and corporate network-
ing requirements, are included in the system. The combining experimentation
through modelling and observation using scenarios enable students to construct
their own knowledge (Chen, 2003), which might be especially important for
learners from a nontechnical background (Kolb et al., 2000).
WebLan-Designer was trilled for the first time during semester 1 of 2005 in three
classes, and the informal feedback from students was positive. We asked the
teaching community in New Zealand to send us comments, and we hoped to
receive feedback from visitors to the Web site. At the time of writing, we have
received comments from seven lecturers involved in teaching networking (three
from AUT, three from other New Zealand institutions, and one from an overseas
university). The responses are positive (see Table 3) and confirm the validity of
the educational benefits stated above, as lecturers perceive the tool’s compo-
nents as valuable and express interest in using WebLan-Designer in class.
The critical comments are about improving the presentation (spelling and typos)
and also about the need to use the tool with care as not to create an illusion of
“easiness” while trying to make it easy to learn. We agree with these comments
wholeheartedly. The suggested improvements include adding more functions
and adding more internal links; we will consider these suggestions carefully in our
future work.

32 Sarkar & Petrova
Concluding Remarks
The design of a new networking tutorial suite (named WebLan-Designer)
follows our previous efforts in both a flexible teaching and learning model
(Petrova, 2002) and a tool to enhance teaching and learning (Sarkar, 2004;
Sarkar & Lian, 2003). WebLan-Designer is a Web-based interactive tool for
teaching and learning LAN design. The tool can be used either in the classroom
to enhance the lecture environment or at home (i.e., off campus) as an aid to
enhance learning various aspects of computer networking and LAN design
(Reinig & The, 1998). Objectifying network topology concepts is one of the
aspects of the constructivist approach towards teaching computer networking.
As WebLan-Designer provides both visual and animated representations, it
supports constructivist pedagogical approaches and can improve students’
participation in flexible learning activities (Chen, 2003). The flexibility in
modelling LAN design enhances learning as it introduces variation — an
experience stimulating the understanding of the concept under investigation
(Berglund, 2003). Both flexibility and variation provide opportunities for students
to build and refine their own knowledge, which they can apply further to solve
Table 3. Evaluation by peers
Positive
… I like the network designer part especially (i.e., the physical star logical bus, etc.).
… Web-based questions and answers are useful for students. I have experienced that students like to use
these for self-review. The different scenarios are useful for students to see and analyze different network
configurations.
… Easy-to-use tutorial and good interface, helpful for learners especially to review and test their
knowledge on wireless LAN, useful Links is a very good idea, especially for students who would like to
explore and learn more.
… A very useful resource … good for learning. (2)
… Interested to use WebLan-Designer … in class. (2)
Critique
… A link from task 5: wireless Design Exercises to Scenarios/Exercises required.
… Some spelling mistakes in the quiz texts.
… A couple of [typographical] errors in your LAN test … [suggested corrections].
… The modeller part may help the visualization of the different network layouts but may also convey an
oversimplified idea of network design.
Recommendations
… More navigation links might make the tutorial easier to navigate and use; for example, after completing
the quiz, there is a link to reattempt the quiz. Similarly links to other parts of the Designer such as tutorial
might make it more navigable.
… There can be more user-friendly feedback and interaction features added.
… It would be helpful to have some graphic-related questions too (i.e., a picture of a network and a
multiple-choice question set about what it is called, etc.). It looks good for the students for revision
especially.
… A usability testing may also be done.

WebLan-Designer 33
problems and develop deeper understanding of properties and relationships — a
necessary component of self-learning (Shifroni & Ginat, 1997).
Compared to the traditional method of classroom teaching of computer network-
ing, WebLan-Designer provides students a different way of learning more LAN
design concepts (e.g., modelling component of the tool). The mixed (and often
very minimal) level of prior student knowledge, recognised by R. K. C. Chang
(2004) as one of the challenges in teaching computer networks, is addressed by
the inbuilt flexibility. More experienced students can go through quizzes and
scenario-based LAN design. Students exposed to networking for the first time
can do a walk-through and learn about computer networks. Finally, learning is
further enhanced by multi-coverage of the content (e.g., quiz, key terms, and
review questions have many commonalities) and making the concepts interesting
and engaging (e.g., when working with the scenarios). Students are given the
opportunity to identify their misconceptions and reconstruct their knowledge,
which helps them internalise, rather then absorb, the basic ideas and concepts
(Chen, 2003).
The tool has some limitations. Currently, WebLan-Designer displays LAN
diagrams with up to 20 workstations, four file servers, and four printers. The
software can easily be upgraded to accommodate any number of components.
The incorporation of wireless personal area networks (Bluetooth technology) is
also suggested for future work. Other developments might include expanding the
scope of the tool to include interactive content at the higher layers of the TCP/
IP protocol stack, such as NAT translation and IP subnetwork modelling.
WebLan-Designer is available at no cost to faculty interested in using it to
supplement their teaching. More information about WebLan-Designer can be
obtained by contacting the first author or through the WebLan-Designer Web
site at http://elena.aut.ac.nz/homepages/weblandesigner/.
Acknowledgments
This work was supported in part by AUT’s RELT Contestable Grant (Grant No.
CJ9987105000, 2004). An earlier version of this chapter appears as: Sarkar, N.,
& Petrova, K. (2005, June). WebLan-Designer: A Web-based system for
interactive teaching and learning LAN design. Proceedings of the 3rd Inter-
national Conference on Information Technology: Research and Education
(ITRE 2005).

34 Sarkar & Petrova
Summary
Interactive teaching and learning by using software tools is an attractive solution
to motivate students to learn a rather technical and dry subject such as LAN
design. This chapter described a Web-based tool called WebLan-Designer that
gives students an interactive and flexible learning experience in both wired and
wireless LAN design. Both teacher and students can benefit from the use of
WebLan-Designer in different teaching and learning contexts. A teacher is able
to use it in the classroom as a demonstration, to liven up the traditional lecture.
Students, on the other hand, can use the system in achieving the following
learning outcomes: (1) complete tutorials on both wired and wireless LAN
design; (2) test prior knowledge on networking through interactive quizzes; (3)
verify the solution to in-class tasks and exercises through LAN modelling; and
(4) learn more about scenario-based LAN design. In addition to enhancing face-
to-face teaching by including an element of online learning in the classroom,
WebLan-Designer provides online support for off-campus students and facili-
tates learning through flexible course delivery. The effectiveness of WebLan-
Designer as an aid to teaching and learning LAN design has been evaluated both
by students and teaching team.
Key Terms and Definitions
Access point (AP): AP stands for access point. Typically, infrastructure-based
wireless networks provide access to the wired backbone network via an
AP. The AP may act as a repeater, bridge, router, or even gateway to
regenerate, forward, filter, or translate messages. All communication
between mobile devices has to take place via the AP.
Ad hoc network: A class of wireless network architecture in which there is no
fixed infrastructure or wireless access points. In ad hoc networks, each
mobile station acts as a router to communicate with other stations. Such a
network can exist on a temporary basis to share some resources among the
mobile stations.
Constructivism: A theory of learning which regards learning as a process of
developing knowledge through the construction and reconstruction of
concepts and ideas, providing learners with motivation, and supporting self-
directed learning. It suggests that learners are particularly likely to make
new ideas when they are actively engaged in making some type of external
artifact, which they can reflect upon and share with others (http://
mia.openworldlearning.org/constructivism.htm).

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